You mentioned Chase, I have a chase performance business checking account that comes 2 outgoing wires free every month and unlimited incoming wires

That should leave you with a quality and lasting finish productJust be sure when getting your estimate you and your contractor you are aware of exactly what work he plans to perform. 

The plan would be perform improvements and refi out, returning my grandparents money in 9-12 months.How would you go about structuring a deal with this scenario?

OSHA can perform a random walk down of a residential home but they often will not.

The beauty of it is that you receive all the money at closing (acquisition + rehab). 

Along with hired workers he will be performing the rehab.

Going in my plan was to spend about $45k and 3 months and the Hope was to refi for $200k+ to pull out $145k and then rent units for $600 each, and cash flow around $500-1,000 each month and pull out my cash investment and in essence have a performing that I had only $10k-ish of my cash invested after the refi.

Our 4Plex is performing great and it has been the best move we have ever made!

Identify what you do the best out of all the tasks performed on this flip and same for your partner.

People think I'm crazy for having an accounting degree and wanting to move away from traditional W2 income into performance pay.